Flow sensing valve

ABSTRACT

A screwdriver system of the automatic type wherein screws are individually delivered to the head of a screwdriver as they are driven. The system includes a flow responsive valve which creates a signal in response to the starting and stopping of the flow of power fluid to the screwdriver and this signal controls a screw delivery mechanism.

United States Patent Bangerter Mar. 14, 197 2 [54] FLOW SENSING VALVE 2,154,811 4/1939 Goss ..l37/118 2 951 516 9/1960 Chilton ..144/32 t I l 1 1 [72] or Kenneth R Eugene" Ithaca N Y 2,803,274 8/1957 Zubal et al ..144/32 [73] Assignee: Ingersoll-Rand Company, New York, NY.

Feb. 17, Examiner-Donald Sch ran Attorney-Carl R. Honen and David W. Tibbott [21] Appl. N0.: 12,111

[57] ABSTRACT [52] U.S.Cl ..l44/32, 137/118 A screwdriver System of the automatic type wherein Screws [51] q 0 23/04 are individually delivered to the head of a screwdriver as they Fleid "E Search i8, are driven The System includes a flow responsive valve which creates a signal in response to the starting and stopping of the [56] References Cited flow of power fluid to the screwdriver and this signal controls UNITED STATES PATENTS a screw delivery mechanism.

2,973,021 2/1961 Crossen 144/32 4 Claims, 2 Drawing Figures 1 32 i 31 I so I 2? i 26 34 l 25 ggzg 1 SCREW 4 DELIVERY MEANS l2 PMENTEBMARMIQYZ RBABJ'AA DELIVERY MEANS l2 INVENTOR E/V/VETH R 1 11? TEA? ATTORNEY FLOW SENSING VALVE- BACKGROUND GF INVENTION This invention relates generally to fluid powdered fastener driving systems and more particularly to the automatic type of system wherein fasteners are automatically delivered to the tool following the driving of a fastener.

This invention is an improvement of the system shown in U.S. Pat. No. 3,301,284 issued to .I. M. Clapp on Jan. 31, 1967. The above patent discloses an automatic screwdriver system wherein a screw is delivered to the screw driver in response to an air signal created by the vertical movement of the screwdriver on a support. Since the signal is created by the relative movement of the screwdriver on a fixed support, the screwdriver cannot be of the portable type which is carried in the hand of the operator like an ordinary screwdriver of the nonautomatic type (a screwdriver wherein screws are manually inserted into the finder of the screwdriver).

SUMMARY OF THE INVENTION The principle object of this invention is to provide an automatic fastener driving system of the fluid-powered type wherein the fastener driver can be supported in and carried about by the hand of the operator, without requiring that the driver be supported on a fixed support.

Other important objects of this invention are: to provide an automatic fastener driving system in which a fastener is delivered to the driving tool in response to the stopping of the flow of power to the tool; to provide a flow responsive means for use in an automatic fastener driving system which is operative in response to the starting and stopping of the flow of power to the driving tool; and to provide a signal creating means for use in controlling a fastener delivery system for a power tool.

In general, the foregoing objects are attained in a system including a fluid-powered fastener driving tool, a power supply, a conduit interconnecting the power supply with the tool, a fluid-powered fastener delivery system connected to the tool and operative to deliver a fastener to the tool in response to a fluid signal and a signal generating means located in the supply conduit and operative to create a fluid signal in response to the flow of power fluid to the tool, to operate the fastener delivery system. The valve means includes a movable member which moves from a closed position toan open position in response to the flow of power fluid'to the tool and, in doing so, creates a fluid signal which operates the fastener delivery system. When the flow of power fluid to the tool stops, the valve means returns to its closed position creating a second signal which also operates the fastener delivery system.

BRIEF DESCRIPTION OF DRAWING The invention is described in connection with the accompanying drawings wherein:

FIG. 1 is a schematic view of the screwdriver system of this invention; and

FIG. 2 is a fragmentary view of a portion of FIG. 1 showing the fluid signal valve in an open position.

DESCRIPTION OF PREFERRED EMBODIMENT It is useful in understanding the subject invention for one to review the disclosure in the previously mentioned U.S. Pat. No. 3,301,284. Looking at the drawing in this application, a fluid-powered screw driver 1 is connected to a fluid power supply conduit 2 and includes a casing 3, a front nose 4, a screw driving blade 5, and a screw delivering passage 6 exiting into the nose 4 adjacent the blade 5. FIG. 1 illustrates a screw 7 located in the driving position in the nose 4 above a workpiece 8.

The screwdriver I is of the type which is automatically started by the operator pressing the screw 7 against the workpiece 8. In other words, power fluid is automatically admitted to the motor of the screwdriver in response to the rearward movement of the driving blade 5 caused by the screw 7 being pressed against the workpiece 8. An example of this type of screwdriver is disclosed in U.S. Pat. No. 3,266,537 issued to Otmar M. Ulbing on Aug. 16, 1966.

The screw delivery passage 6 is connected to a screw delivery hose 10 at the rear of the screwdriver. The hose 10 extends from a fastener delivery means 12 schematically shown in the drawing as a box. No effort is made to disclose the details of the fastener delivery means 12 since these details are well known in the art. For example, one embodiment is disclosed in U.S. Pat. No. 3,301,284, previously mentioned in this application. The fastener delivery means 12 is controlled by a fluid signal in a signal line 14.

A flow responsive signal valve 16 is connected between the fluid power supply conduit 2 and a power line 17 extending from a power supply 18. The valve 16 includes a power fluid inlet 20, a power fluid outlet 21, and a fluid signal port 22. The signal port 22 is connected to the signal line 14. The valve 16 includes an annular bore 25 containing a reciprocating valve disc 26. FIG. 1 shows the valve disc 26 in its closed position wherein fluid cannot flow between inlet 20 and outlet 21. A light spring 27 urges the valve disc 26 to its closed position. The valve bore 25 is stepped so that as valve disc 26 moves toward its open position, as shown in. FIG. 2, it moves into a portion of the bore 25 which is of larger diameter than the disc 26 wherein the fluid can readily flow through the valve from the inlet 20 to the outlet 21. The valve spring 27 is very weak so that there is very little pressure drop across the valve disc during the flow of fluid around it.

In addition, when the valve disc 26 moves to its open position, fluid flows from the inlet 20 to the signal port 22, to create a signal. The valve disc 26 is connected to a valve stem 30 which slides in a passage 31 which extends from the valve bore 25 through the end of the body of the valve 16. The signal port 22 opens into the passage 31 and the valve stem 30 carries an O-ring 32 around its neck where it seats on and closes the inner end of the passage 31 to prevent fluid from flowing into the passage when the valve disc 26 is in its closed position as shown in FIG. 1. The stem 30 contains a longitudinal groove 34 which interconnects the signal port 22 to the atmosphere when the valve is closed. When the valve stem 30 moves to the position shown in FIG. 2, it closes off the passage 31 from the atmosphere and the unseating of the O-ring 32 allows fluid to flow through the groove 34 into the signal port 22 and thence into the signal line 14.

The fluid signal in the signal line 14' created by the opening of the valve 16 causes the screw delivery means 12 to begin to cycle and to start the delivery of a fastener. This cycle will not be complete until the screwdriver 1 drives the screw and completes the driving cycle. The screw delivery means 12 will know when the screw driving cycle is completed by sensing the stopping of the fluid signal. Hence it will wait until the discontinuance of the fluid signal through line 14 before completing the delivery of the screw to the tool. This is described in the aforesaid U.S. Pat. No. 3,301,284.

When the screwdriver completes the driving of the screw and the operator raises the screw driver 1 from the workpiece 8, the throttle of the screwdriver will automatically close, thereby stopping the flow of power fluid through the valve 16. When this happens, the valve disc 26 will return to its closed position, shown in FIG. 1, the fluid flowing to the signal port 22 will be discontinued and the signal port will be vented to the atmosphere through the groove 34. This venting of the signal port 22 to the atmosphere will cause the screw delivery means 12 to complete the delivery of a screw to the screwdriver 1.

While only a single embodiment of the invention is described and illustrated in detail, this: invention is not limited simply to this embodiment but incorporates other embodiments and variations which utilize the concepts and teachings of the invention.

I claim:

1. In a power fastener driving system, the combination comprising:

includes a valve acted on by said power fluid and movable between open and closed positions in response to the flow of said power fluid through said conduit.

3. The combination of claim 2 wherein:

said valve is operative to create a fluid signal as it moves between its open and closed positions. 7

4. The combination of claim 3 wherein:

said valve is operative to discontinue the fluid signal as it moves from its open position to its closed position. 

1. In a power fastener driving system, the combination comprising: a fluid-powered fastener driving tool; a conduit connecting said power supply to said tool; a fluid-powered fastener delivery system connected to said tool and operative to deliver a fastener to said tool in response to a fluid signal; and signal means connected in said conduit and operative, in response to the flow of fluid through said conduit, to create a fluid signal to operate said fastener delivery system, said signal means being non-responsive to a change of pressure in said conduit.
 2. The combination of claim 1 wherein: said signal means includes a valve acted on by said power fluid and movable between open and closed positions in response to the flow of said power fluid through said conduit.
 3. The combination of claim 2 wherein: said valve is operative to create a fluid signal as it moves between its open and closed positions.
 4. The combination of claim 3 wherein: said valve is operative to discontinue the fluid signal as it moves from its open position to its closed position. 